U.S. Pat. No. 6,401,270 to Moore, incorporated herein in its entirety by this reference, discloses a conventional hydraulic toilet in which positive pressure is used to facilitate discharging waste from a toilet pan or bowl. A closeable lid may be sealed to the bowl to define a chamber, with an air displacement unit connected to the chamber utilized to increase air pressure therein. The toilet of the Moore patent is not a vacuum type, however, and the Moore patent neither contemplates nor suggests means for reducing noise associated with operation of the toilet.
Unlike the Moore patent, U.S. Pat. No. to Olin, et al. (also incorporated herein in its entirety by reference) does detail a vacuum-type toilet. According to the Olin patent, operational noise of the toilet may be diminished through use of “a lid forming a substantially airtight and soundproof closure at the top of the bowl.” See Olin, Abstract, 11. 15-17. Air may be supplied to the toilet bowl via a tube or pipe entering at the back thereof if closing the lid results in too little air being present in the bowl for efficient flushing of waste. The Olin patent does not, however, address reducing water consumption in such a toilet design.